1. Field of Invention
This invention relates to a method of welding of metal plates conducted in a solid phase. This invention can be applied in the area of composite multilayer metal products manufacturing by solid-phase welding under pressure and can be introduced to various sectors of industry, such as: metallurgy, automotive, instrument making and other industries.
2. Description of Related Art
In the process of moldability treatment under pressure, various layers in sandwiched products are composed of different metals and deformed unevenly, this happens because while different metals are reaching moldability state they rest on different deformation points. Due to uneven layer deformation, significant residual stresses are produced in layers, products are subject to corrugation and adherence of the layers is significantly reduced.
A known solid-phase welding method describes sandwiching metal plates together with additional metal lining inserted between plates to create a package, heating this package in vacuum, placing it between special cylinders and deformation of the package in vacuum (USSR patent No. 565801, B23P 3/06, 1977) [1]. The package is placed between cylinders of same diameter. To improve isotropic properties of finished products, before metal plates are sandwiched together in a package, their contacting surfaces shall be riffled by applying evenly distributed longitudinal channels.
In the course of concurrent deformation of superimposed plates, it is mandatory to achieve the most even distribution of deformation force on the surfaces of plates in all layers to achieve their best possible adhesion. This provides renewal of the bonded surfaces and intensifies adhesion processes improving bonding strength between the layers. Deformation level on surfaces bonded with the purpose to acquire flat bimetallic materials (caeteris paribus—other conditions being equal (lat.)) shall be determined on the basis of distributing vertical volumetric movements, conditioned, along with other conditions, by movements of deforming instrument.
When bonded plates are deformed by cylinders rotated with similar velocities, as it is done according to method [1], placement of plates in the package in relation to cylinders has no influence on the intensity of interlayer deformations that is cohesion strength between layers in this case is low.
A known method of production of flat bimetallic materials (RU patent No. 2082575, B23K 20/04, 1997) [2] can be used as a prototype for the method of the invention. This method consists of following stages: metal plates are superimposed to form a sandwich, which is placed between two rotating cylinders of different diameter, heated and deformed by the cylinders. In the process of deformation, the plate with smallest thickness shall be placed in contact with the cylinder having higher rotation velocity.
Despite the current developments, an improvement in the process of welding of metal plates is desired.
All references cited herein are incorporated herein by reference in their entireties.